Stage matched interventions for stress management that are interactive and individualized, and are delivered proactively to entire populations can have unprecedented impacts. Computer based expert systems linked to self-help manuals can be as effective as Counselors but at much lower cost and greater accessibility. Stress is an important cause of cancer and other chronic and acute diseases and is one of the most costly behaviors in terms of health care, job performance and disability. Fifty million Americans do not practice effective stress management. Existing programs are action- oriented and are designed for the 30% of populations who are prepared to take action. Stage matched programs can meet the needs of all; the 45% in the Precontemplation stage and the 25% in the Contemplation stage. Phase I of this Fast-Track research will demonstrate the feasibility of recruiting 70% of at-risk populations and the acceptability of the expert system interventions. Phase II will complete recruitment of 1200 participants randomly assigned to treatment or control and can demonstrate efficacy of these interventions over six months. Follow-up over 18 months can show increasing impact long after the intervention. Effective and cost-effective stress management systems can be broadly disseminated with consistent quality and user friendly acceptability. PROPOSED COMMERCIAL APPLICATIONS: Stress is one of the most costly conditions for individuals, employees and health care systems. Fifty million Americans do not practice effective stress management. Effective and cost effective expert systems that can treat stress on a population basis have outstanding commercial impact.